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Summary of Significant Accounting Policies (Details) - USD ($) $ in Millions | 12 Months Ended
--- | ---
Dec. 31, 2018 | Dec. 31, 2017 | Dec. 31, 2016
Cash Equivalents and Short-term Investments [Abstract] |  |  |
Short-term investments | $ 3.8 | $ 2.7 |
Unrealized holding gains and losses on short-term bank investments | $ 0.0 |  |
Trade Accounts Receivable [Abstract] |  |  |
Past due threshold for individual collectability review | 90 days |  |
Property, Plant and Equipment [Abstract] |  |  |
Initial term of long term evergreen contracts | 10 years |  |
Investment in Joint Ventures [Abstract] |  |  |
Equity method investment | $ 17.8 |  |
Operating Income (Loss) [Abstract] |  |  |
Marketing and administrative expenses | (178.6) | (180.7) | $ (176.4)
Other deductions | $ (1.5) | (6.2) | 0.8
Buildings [Member] | Minimum [Member] |  |  |
Property, Plant and Equipment [Abstract] |  |  |
Annual rates of depreciation | 3.00% |  |
Buildings [Member] | Maximum [Member] |  |  |
Property, Plant and Equipment [Abstract] |  |  |
Annual rates of depreciation | 6.67% |  |
Machinery and Equipment [Member] | Minimum [Member] |  |  |
Property, Plant and Equipment [Abstract] |  |  |
Annual rates of depreciation | 6.67% |  |
Machinery and Equipment [Member] | Maximum [Member] |  |  |
Property, Plant and Equipment [Abstract] |  |  |
Annual rates of depreciation | 12.50% |  |
Furniture and Fixtures [Member] | Minimum [Member] |  |  |
Property, Plant and Equipment [Abstract] |  |  |
Annual rates of depreciation | 8.00% |  |
Furniture and Fixtures [Member] | Maximum [Member] |  |  |
Property, Plant and Equipment [Abstract] |  |  |
Annual rates of depreciation | 12.50% |  |
Computer Equipment and Software-related Assets [Member] | Minimum [Member] |  |  |
Property, Plant and Equipment [Abstract] |  |  |
Annual rates of depreciation | 12.50% |  |
Computer Equipment and Software-related Assets [Member] | Maximum [Member] |  |  |
Property, Plant and Equipment [Abstract] |  |  |
Annual rates of depreciation | 25.00% |  |
PCC Production Facilities [Member] |  |  |
Property, Plant and Equipment [Abstract] |  |  |
Estimated useful life | 15 years |  |
Machinery and Equipment for Natural Stone Mining and Processing Plants and Chemical Plants [Member] |  |  |
Property, Plant and Equipment [Abstract] |  |  |
Estimated useful life | 15 years |  |
Accounting Standards Update 2016-02 [Member] | Minimum [Member] |  |  |
Assets and Liabilities, Lessee [Abstract] |  |  |
Operating lease liability current | $ 60.0 |  |
Operating lease, ROU assets | 50.0 |  |
Accounting Standards Update 2016-02 [Member] | Maximum [Member] |  |  |
Assets and Liabilities, Lessee [Abstract] |  |  |
Operating lease liability current | 65.0 |  |
Operating lease, ROU assets | $ 55.0 |  |
Accounting Standards Update 2017-07 [Member] |  |  |
Operating Income (Loss) [Abstract] |  |  |
Marketing and administrative expenses |  | (1.7) | (3.0)
Other deductions |  | $ 1.7 | $ 3.0

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